public class Example4_20 {
    public static void main(String args[]) {
	char a[] = {'a','b','c','D','E','F'};
	for(int i=0;i<a.length;i++) {
	    if(Character.isLowerCase(a[i]) )
		a[i] = Character.toUpperCase(a[i]);
	    else if(Character.isUpperCase(a[i])
		a[i] = Character.toLowerCase(a[i]);
	}
	for (int i=0; i<a.length;i++)
	    System.out.print(" "+a[i]);
	}
}
